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| author | Chris Lattner <sabre@nondot.org> | 2010-10-01 05:51:02 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-10-01 05:51:02 +0000 |
| commit | c663a6738460bfce20a019fa4a6e647b92073a1b (patch) | |
| tree | 495c5318ffec2073ce4cbf832a76e973c79e92dd | |
| parent | 98e82678bdbe2aaaaa1e0ad47c4d898e74475ef0 (diff) | |
| download | bcm5719-llvm-c663a6738460bfce20a019fa4a6e647b92073a1b.tar.gz bcm5719-llvm-c663a6738460bfce20a019fa4a6e647b92073a1b.zip | |
fix PR8267 - Instcombine shouldn't optimizer away volatile memcpy's.
llvm-svn: 115296
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/memcpy.ll | 15 |
2 files changed, 18 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp index 0ebe3b45589..ed078ec1c51 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp @@ -280,7 +280,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) { // memmove/cpy/set of zero bytes is a noop. if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { - if (NumBytes->isNullValue()) return EraseInstFromFunction(CI); + if (NumBytes->isNullValue()) + return EraseInstFromFunction(CI); if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) if (CI->getZExtValue() == 1) { @@ -289,6 +290,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) { // alignment is sufficient. } } + + // No other transformations apply to volatile transfers. + if (MI->isVolatile()) + return 0; // If we have a memmove and the source operation is a constant global, // then the source and dest pointers can't alias, so we can change this diff --git a/llvm/test/Transforms/InstCombine/memcpy.ll b/llvm/test/Transforms/InstCombine/memcpy.ll index 421156d7712..8a2e3aaad02 100644 --- a/llvm/test/Transforms/InstCombine/memcpy.ll +++ b/llvm/test/Transforms/InstCombine/memcpy.ll @@ -2,9 +2,18 @@ declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind -define void @test4(i8* %a) { +define void @test1(i8* %a) { tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a, i8* %a, i32 100, i32 1, i1 false) ret void -} -; CHECK: define void @test4 +; CHECK: define void @test1 ; CHECK-NEXT: ret void +} + + +; PR8267 +define void @test2(i8* %a) { + tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a, i8* %a, i32 100, i32 1, i1 true) + ret void +; CHECK: define void @test2 +; CHECK-NEXT: call void @llvm.memcpy +} |
